Wow! What a way to watch a molting tarantula. This time-lapse video of a pet Mexican red-knee tarantula shedding its exoskeleton takes just 40 seconds, rather than 3 hours of real time, and it's fascinating to say the least. Although just posted on YouTube, the video is actually from 2017, when National Geographic said:
This tarantula is a juvenile, according to its owner Jason Bauer, who shot the video footage. That means it will molt several more times in its life.
During the molting process, tarantulas contract their abdomens, which pushes fluid into the upper body, or cephalothorax. The fluid increases the pressure already on the strained exoskeleton, allowing the tarantula to break through its weak spots.
Andrine Shufran from Oklahoma State University's Department of Entomology put it more simply:
"She essentially pops off the top of her head and pulls her body out."